Our paper is the first to introduce the concept of "Wireless Multimedia
Sensor Network" (WMSN) as a generalization of the notion of "Sensor
Network." A multimedia sensor network can be understood as a network of
wirelessly interconnected devices that are able to ubiquitously retrieve
multimedia content such as video and audio streams, still images, and
sensor data from the environment, fostered by the recent availability of
low-cost cameras, sensors, and microphones. In addition, our paper
systematically outlines the major research challenges of this new field
that can potentially have a profound impact on our daily activities.

In our paper, after discussing futuristic applications of WMNSs, we analyze
the state of the art in algorithms, protocols, and hardware for wireless
multimedia sensor networks, and discuss open research issues in detail.
Furthermore, we discuss architectures for WMSNs, along with their
advantages and drawbacks. We believe that our paper is and will be an
important resource for researchers interested in this field in years to
come.

Does it describe a new discovery, methodology, or
synthesis of knowledge?

Our paper constitutes certainly a synthesis of knowledge, but it goes
beyond that by outlining open research issues and proposing a new research
area. We believe that our paper will encourage and inspire many researchers
to enter this field, and the high number of citations that the paper has
received so far seems to confirm this.

Would you summarize the significance of your paper in
layman's terms?

With rapid improvements and miniaturization in hardware, a single device
can be equipped with audio and visual information collection modules. By
deploying a large-scale network of such devices and by interconnecting them
through wireless links, our ability to observe the physical environment can
be greatly enhanced. For example, multimedia sensors could infer and record
potentially relevant activities (thefts, car accidents, traffic violations)
and make video/audio streams or reports available for future query. It will
be possible to monitor car traffic in big cities or on highways and deploy
services that offer traffic routing advice to avoid congestion.

Moreover, multimedia sensors may monitor the flow of vehicular traffic on
highways and retrieve aggregate information such as average speed and
number of cars. Sensors could also detect violations and transmit video
streams to law enforcement agencies to identify the violator, or buffer
images and streams in case of accidents for subsequent accident scene
analysis.

Coauthor
Tommaso Melodia

Another important potential area of application of this technology is
advanced health care delivery. Telemedicine sensor networks can be
integrated with XG multimedia networks to provide ubiquitous health care
services. Patients will carry medical sensors to monitor parameters such as
body temperature, blood pressure, pulse oximetry, ECG, breathing activity,
while remote medical centers will perform advanced remote monitoring of
their patients via video and audio sensors, location sensors, motion or
activity sensors, which can also be embedded in a wrist device.

Multimedia sensor networks can also be used to monitor and study the
behavior of elderly people as a means to identify the causes of illnesses
that affect them. Networks of wearable or video and audio sensors can infer
emergency situations and immediately connect elderly patients with remote
assistance services or with relatives.

How did you become involved in this research, and were
there any problems along the way?

Ian F. Akyildiz: In my research spanning the past several decades, I have
always envisioned future directions where technology can be put to better
use. My survey on wireless sensor networks is one of the most-cited
articles in the field of networking, and I had also published several
research papers on the topic of quality of service for multimedia
applications.

I believed that the recent improvement in hardware platforms, the need for
visual monitoring over simple plain-text data, and a growing social
awareness for connectivity would be the primary forces driving multimedia
research. Thus, my background and experience in this area led me to pursue
the design of WMSNs, which was a challenge given the constrained operation
of the devices. This, together with a great team composed by my co-authors
Tommaso Melodia and Kaushik Chowdhury, led to this highly successful
publication.

One of the main problems was convincing the research community in general
about the feasibility of this technology. I wished to stress on the
practical and implementable aspect of multimedia sensors over describing a
theoretical outline. For this, the protocol design approaches and the
existing hardware support needed to mutually supportive.

While writing the article we had to adapt our vision to the existing state
of the art, and not merely relying on possible future node architectures.
We had to often go back to the drawing board to redesign a protocol or
suggest alternate paths, if there was no immediate hardware support.
Moreover, this area covers a very diverse range of specializations, from
coding theory, systems design, to higher layer protocols. This paper has
also been a learning process for me, as I had to refer to several new
concepts and ideas, not immediately connected with my current research.

Where do you see your research leading in the
future?

Ian F. Akyildiz: Efforts from several research areas will need to converge
to develop efficient and flexible WMSNs, and this in turn, will
significantly enhance our ability to interact with the physical
environment. These include advances in the understanding of
energy-constrained wireless communications, and the integration of advanced
multimedia processing techniques in the communication process.

Another crucial issue is the development of flexible system architectures
and software to allow querying the network to specify the required service
(thus providing abstraction from implementation details). At the same time,
it is necessary to provide the service in the most efficient way, which may
be in contrast with the need for abstraction.

As sensor platforms diversify, ranging from static nodes that have
restricted computational ability to sensors on vehicular networks and
mobile phones, I envision the need for re-visiting classical multimedia
networking. Audio and video data may originate and be communicated over
diverse network architectures between a given source and destination pair,
and effectively meeting the performance constraints in such scenarios is a
challenge. My research will address all the above factors that are likely
influence our multimedia access in the near future.

Do you foresee any social or political implications for
your research?

The development of WMSNs has important implications from several
perspectives. For example, it may have implications for criminal justice
policy and practice. The technology has the potential to enable
large-scale, low-cost deployment of unattended smart cameras and other
multimedia sensors, which are able to process, correlate and fuse in
real-time information from heterogeneous sources.

These systems will enhance the ability of law enforcement and correction
officers to observe and monitor locations and events in an unprecedented
way, since WMSNs can be enhanced with distributed processing and computer
vision techniques that will allow performing sophisticated real-time data
analysis to detect weapons, identify suspicious individuals, or infer
potentially dangerous activities.

While this technology is likely to raise concerns from civil liberties
advocates worried about the creation of a surveillance society, if properly
regulated, technology for advanced surveillance can actually even be
supportive of privacy interests and not simply a means to create a
surveillance society.